Not super famous.
One girl I went to HS with has a pretty fancy cake shop now, and she's been featured on Food Network a few times:
http://spicedblog.com/baker-intervie...matsubara.html
A guy from my daughter's high school has recently hit it pretty big on the Nashville scene. He's a few years older than she is, so she didn't know him at all. But he's sorta a legend around there right now. His name's Shay Mooney, and he's part of the group Dan & Shay. They had a pretty big hit with this song:
https://www.youtube.com/watch?v=S-Ac3uVAPZY
And just a couple weeks ago, a guy I went to HS with (and actually had a crush on when we were in elementary school) was arrested for murder (and he totally did it). So, I guess that makes him "famous" but not quite in the celebrity way. :/